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Post by Roger on Dec 15, 2020 22:59:59 GMT
I'm machining both hex features in one operation, leaving enough meat on the shaft to stop the end from flexing too much. 20201215_205215 by Roger Froud, on Flickr It's better to turn precision diameters than try to do it on the mill. 20201215_212014 by Roger Froud, on Flickr The hex is a nice easy fit in the valve element without being loose. I don't want it tight because it will spread the material and bind in the valve housing. 20201215_221512 by Roger Froud, on Flickr
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dscott
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Post by dscott on Dec 16, 2020 1:10:02 GMT
![](https://i.imgur.com/mrVgLC5.jpg) I had to take mine apart to bang the jaws out as they were very rusty. Lucky that I arranged this photo showing the inner workings. Yes it now lives on the first Super 7 and is used when I go and have a go for an alternative to Workshop Building. Such a simple concept to get things to run true. David and Lily.
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Post by Roger on Dec 16, 2020 8:15:18 GMT
![](https://i.imgur.com/mrVgLC5.jpg) I had to take mine apart to bang the jaws out as they were very rusty. Lucky that I arranged this photo showing the inner workings. Yes it now lives on the first Super 7 and is used when I go and have a go for an alternative to Workshop Building. Such a simple concept to get things to run true. David and Lily. Thanks for that David, I've not seen inside of one but it's pretty much how I imagined. So be honest it wouldn't take much to design an arrangement using a standard chuck and backplate to achieve the same thing. You only have to turn off a little of the register to allow for the necessary movement and change the clamping bolt arrangement to allow it to slide. I think you could have shallow angled tapered holes in the back face of the chuck, and under mating tapered bolts on a larger pitch to force into them to move the chuck. Ok, the bolts may require bosses that stand out the rear of the backplate, but there's usually a lot of clearance there. Once you've had one of these, you'll never want to go back. It's very rare for me to use the 4-jaw because of it, and the accuracy of my work is much improved.
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jem
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Post by jem on Dec 16, 2020 16:37:59 GMT
Hi Roger,
of cause, I should have worked that out.Strange how bsp prevails!!
best wishes
Jem
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Post by Roger on Dec 16, 2020 22:52:00 GMT
I'm making the handle of the 3-Port Valve as a 'T' shape in Tufnol. The idea is that the 'T' shape mimics the internal ports on the valve element so I can see which position it's in. In reality there are only two useful positions, so there could have been stops but I didn't think it was worth the effort of designing that. As it happens, it would be interesting to see how the injector behaves when it's faced with at restricted or blocked outlet. Anyway, here it is with the Hex pocket being checked for size. 20201216_124327 by Roger Froud, on Flickr I'd also forgotten that I'll need to pipe the overflows on the locomotive, so I've designed and started machining the flanged pipe fittings. These probably don't warrant an O-ring, but they're getting one anyway since it's so easy to do. 20201216_211513 by Roger Froud, on Flickr The reverse side needs a shallow recess to locate the pipe once it's been parted off. 20201216_214716 by Roger Froud, on Flickr This is the joining pipe between the 3-Port Valve and the Balanced Clack Valve. As usual there's a ring of fine Silver Solder wire under the flux, and the other end, which has already been Silver Soldered, is protected with Tipped. 20201216_212656 by Roger Froud, on Flickr This is being done it two steps too. The top nipple is already done, and here' the 'Helping Hands' comes in useful for holding the tube vertically in the shallow register. I learned my lesson from the other one where the Silver Solder got into the pipe. This time I've coated the inside with Tippex too. 20201216_221329 by Roger Froud, on Flickr 20201216_221514 by Roger Froud, on Flickr So far so good, just the pipe to the clack and the steam pipe to the balanced valve to do... oh, and the overflow flange pipe needs making. Still, I've broken the back of the job, so I'll be finishing it off soon and sorting out the Injector assembly. 20201216_223344 by Roger Froud, on Flickr
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tony9f
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Post by tony9f on Dec 17, 2020 10:09:46 GMT
Morning all,
As a matter of interest, are the adjusting screws and scroll for the Griptru chuch hardened?
Tony
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Post by Roger on Dec 17, 2020 11:14:56 GMT
Morning all, As a matter of interest, are the adjusting screws and scroll for the Griptru chuch hardened? Tony Hi Tony, I don't know, but I would be surprised if they weren't.
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Post by Roger on Dec 17, 2020 21:32:34 GMT
Here's the cross sectioned model of the 8x Injector again so it's clear what parts I'm making below. Fitting the cones was easy once I'd added a chamfer to the ends of the bore where the threads end. However, I'd like a little more room over the O-rings and the thread could benefit from being a little finer. So both goals can be achieved by reducing the pitch from the M7 x 0.75 (fine) to M7 x 0.5 (fine). I've bought a second and bottom tap so I can made the ones that go on the locomotive that size. I had to ease the outside diameter of the Once Piece Cone because I'd managed to leave that oversize and it was a push fit. Now it slides through easily without the O-rings. I don't want the cones to be difficult to get out because the plan is to leave the body on the locomotive and slide out the inside parts if it ever needs to come apart. So I made a Delrin pusher to make sliding the cones and sleeve easier when the O-rings are in place. There's delibarately only a light nip so that they don't get extruded into the overflow and water inlet holes. I was going to leave the Regulation Gap spacer over size, but decided to just go for the size on the drawing instead. It ought to be close, so I'll try that first. I hadn't really thought too much about the implcations of changing the overall length of the cones when I added the cutouts into the sides of end plugs. I just did them up tight without the cones in place and added the cutouts. Of course that means that the length of the cones needs to match the space left. Anyway, I've trimmed the length of the outlet end cap and it's all together pretty much as drawn. I think I'll have to change things slightly at the outlet end by doing the same sort of thing I've done on the inlet end, ie add a separate sleeve that can be adjusted in length.
Sectioned injector with overflow valve spring by Roger Froud, on Flickr Anyway, enough waffle, here's one of the overflow flanges getting the pipe register added on the back. I've just drilled and tapped two holes in a piece of Steel bar and bolted it down. 20201217_111522 by Roger Froud, on Flickr The cutter was a bit blunt, but it's done the job. I do like to get as much value as possible from my cutters! 20201217_112240 by Roger Froud, on Flickr The Helping Hands came in useful again. I've protected the Crocodile clip from the flame which is going to come from the right. 20201217_115013 by Roger Froud, on Flickr 20201217_120758 by Roger Froud, on Flickr 20201217_120818 by Roger Froud, on Flickr This is the chamfering tool for the end of the bore. The ID of the M7 x 0.75 (fine) thread is 6.2mm, and the bore is only 6mm, so you can see why a special tool was required. That was hardened and tempered in the usual way and gently used by hand. It's only a small 30 degree chamfer, but with a light nip on the O-rings, that's all it needed. 20201217_124243 by Roger Froud, on Flickr Now we come to the final part of the Injector that I hadn't made. This is the guide for the Overflow Spring, shown in a muddy green colour on the above section. It's got a 5mm diameter impression in the end of it so that the spring can be as long as possible. I'm using a 5mm Ball nosed cutter to add that. 20201217_185319 by Roger Froud, on Flickr It's pretty small, the shaft is only 1.6mm diameter and the through hole is 1mm so I can add a chain to it. This is a 0.8mm Carbide PCB drill doing that, which was followed up by a 1mm HSS drill. 20201217_191941 by Roger Froud, on Flickr 20201217_192728 by Roger Froud, on Flickr So here's the 5mm Silicon Nitride Ceramic ball sat on top of the cup with the spring underneath. 20201217_193119 by Roger Froud, on Flickr It's mighty fiddly, bolting the housing to the body, I had to add a flat to the bolt heads because they foul the body and won't turn. I might file a recess on the final ones to make that easier. I also had to turn down one of the nuts which was too long to fit in the gap. Once it's on, it will stay on though, so it probably isn't worth bothering with. I can get the outlet pipe off easily enough. 20201217_202400 by Roger Froud, on Flickr So I've still got to attach the water inlet flange to a short length of pipe, make the boiler feed pipe that goes to the Clack, and the Steam feed to the Balanced Clack valve. Hopefully we're only a couple of days away from giving it a try.
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Post by delaplume on Dec 18, 2020 1:26:49 GMT
Hi Roger,
I, like many others on here, have great admiration for the craftmanship that you are producing.......But will you promise me one thing ??....Please, whatever you do with those injectors ( there are 2 don't forget )..don't paint them RED !!...LoL !!
One benefit yours will have is the lack of that dammed "chirping" noise as well......
I bet when Father Christmas drops down your chimney he has an accurate fit with microns to spare ??
Nearly there,----it's always darkest just before the dawn--
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Post by Roger on Dec 18, 2020 8:12:39 GMT
Hi Roger, I, like many others on here, have great admiration for the craftmanship that you are producing.......But will you promise me one thing ??....Please, whatever you do with those injectors ( there are 2 don't forget )..don't paint them RED !!...LoL !! One benefit yours will have is the lack of that dammed "chirping" noise as well...... I bet when Father Christmas drops down your chimney he has an accurate fit with microns to spare ?? Nearly there,----it's always darkest just before the dawn-- Thanks Alan, and no, I won't be painting it Red! It was the way the usual injectors look, including that awful Red paint, that convinced me to make something a little more scale. I have no idea whether it will work or not, we'll have to wait and see.
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Post by andyhigham on Dec 18, 2020 10:11:51 GMT
Just a quick thought. Shop bought injectors could have their looks improved by making the tube nuts look like a pair of flanges bolted together
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Post by 92220 on Dec 18, 2020 12:50:56 GMT
Morning all, As a matter of interest, are the adjusting screws and scroll for the Griptru chuch hardened? Tony Yes they are hardened.
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Post by Roger on Dec 18, 2020 13:14:22 GMT
Just a quick thought. Shop bought injectors could have their looks improved by making the tube nuts look like a pair of flanges bolted together Good idea, and you could use a special spanner that engaged with the cosmetic nut and bolt to tighten them. I did consider this as a way to avoid having tiny bolted flanges, but concluded that although it would look better than a hex nut, it would still not look very scale.
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Post by Roger on Dec 18, 2020 22:13:07 GMT
The original 3-port valve was too stiff to turn when assembled, so I had to make another one. 20201218_174618 by Roger Froud, on Flickr Although this wasn't anywhere near as tight as the first one, it's still pretty stiff when it's all assembled. Still, as long as I can turn it, that's fine. 20201218_174626 by Roger Froud, on Flickr This is the feed pipe from the 3-port valve to the Boiler Clack... 20201218_203558 by Roger Froud, on Flickr ... and this is the 4mm Steam pipe for the balanced clack valve. 20201218_212112 by Roger Froud, on Flickr And finally, the water input flange was Silver Soldered to a short length of Copper pipe and the whole thing assembled. 20201218_214618 by Roger Froud, on Flickr It's a bit of a monstrocity, but it ought to do the job. 20201218_214629 by Roger Froud, on Flickr I just need a three lengths of hose from the Loft for the water suction pipe, the overflow and the delivery from the Balanced Clack Valve. For the time being, I've left the ball out of the delivery clack on the Injector, I'll fit that when it's all working properly so I know it's not in the equation. There are quite enough variables in this new arrangement without adding unnecessary ones. It's too late to play with it now, and I really need a good tidy up before I get stuck into it. At the moment I'd say the chance of immediate success are about 20%, so I'm really not expecting much at first. I'm confident it's made very close to the design drawings, so if it doesn't work, it's almost certainly going to be a design issue. Let the fun begin!
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JonL
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Post by JonL on Dec 19, 2020 12:42:40 GMT
Obviously feel free to ignore this entirely, but I feel maybe this testing is important enough (and worth cataloging) to justify its own "Injector Tests" thread? It would certainly assist those searching on Google for such research.
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tony9f
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Post by tony9f on Dec 19, 2020 13:05:22 GMT
Or maybe go on the injector design thread Roger?
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Post by Roger on Dec 19, 2020 13:53:35 GMT
The clear hose is a real pain because it insists on staying coiled up and won't stay in the container. I've used a heat gun on the RH one so see if I can get it straight, so that seems to be the solution... 20201219_113430 by Roger Froud, on Flickr Which I applied to the Feed pipe. 20201219_115457 by Roger Froud, on Flickr I fitted a clamp to the inlet tube and fired it up, but it wouldn't draw that water up at all. So I put the container on the bench to make it a bit easier but still nothing. Hmmm... Then I could see water dripping out at the joint, so clearly it wasn't sealing. The clip I've got is on the big side, so I rolled up a Stainless Shim and tried again. That picks up the water nicely, but there's just loads of steam issuing from the overflow. So, no big surprise that it didn't work straight off the bat. However, step one demonstrates that the Ejector portion of the design is possibly right, but there doesn't appear to be enough water getting drawn into the Condensing Cone to condense the Steam. That might be for two reasons. 1) The Regulation Gap may be much too small 2) The razor sharp edge on the inlet to the Condensing Cone might need the corner rounding slightly. I can't go far with that because it affects the length of the Condensing Cone. So I think the first thing to do is to double check what regulation gap I think I've got and make a new spacer to increase the gap. I'll probably modify the delivery end cover so I can fit a spacer in that end to accommodate any changed in the overall length of the cone assembly. Another takeaway is that there's no problem with the Steam popping the Overflow Valve open. I'd be surprised if there was though. Whether it will be ok if it does eventually pick up is anyone's guess. So far so good, I'm not disheartened... yet!
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Post by Roger on Dec 19, 2020 13:56:13 GMT
Obviously feel free to ignore this entirely, but I feel maybe this testing is important enough (and worth cataloging) to justify its own "Injector Tests" thread? It would certainly assist those searching on Google for such research. It's a fair point, but it's so speculative at this stage that I don't want to contaminate the 'Designing Injectors' thread with stuff that ultimately doesn't work. If it turns out to be a success, I'll write up a condensed version in that thread so it's a more concise presentation.
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JonL
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Post by JonL on Dec 19, 2020 14:08:03 GMT
I had the same problem with clear hose, I just ran water from the hot tap through it followed by cold.
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Post by Roger on Dec 19, 2020 15:50:42 GMT
I had the same problem with clear hose, I just ran water from the hot tap through it followed by cold. I didn't think of that, it would have been much quicker!
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